Project description:Polycomb Repressive Complex 2 (PRC2) maintains repression of genes specific for other cell types but associates with genes ectopically in cancer. How PRC2 is removed from genes is unknown but this knowledge may allow the targeted reversal of deleterious PRC2 recruitment events. We show that G-tract RNA specifically removes PRC2 from genes in human and mouse cells. PRC2 preferentially binds G-tracts within nascent pre-mRNAs, especially within predicted G-quadruplex structures. G-quadruplex RNA evicts the PRC2 catalytic core from the substrate nucleosome. PRC2 transfers from chromatin to RNA upon gene activation and chromatin-associated G-tract RNA removes PRC2 and depletes H3K27me3 from genes. Targeting G-tract RNA to CDKN2A in malignant rhabdoid tumor cells reactivates the gene and induces senescence. These data support a model in which pre-mRNA evicts PRC2 during gene activation and provides the means to selectively remove PRC2 from specific genes.
Project description:Polycomb repressive complex 2 (PRC2) maintains repression of cell-type-specific genes but also associates with genes ectopically in cancer. While it is currently unknown how PRC2 is removed from genes, such knowledge would be useful for the targeted reversal of deleterious PRC2 recruitment events. Here, we show that G-tract RNA specifically removes PRC2 from genes in human and mouse cells. PRC2 preferentially binds G tracts within nascent precursor mRNA (pre-mRNA), especially within predicted G-quadruplex structures. G-quadruplex RNA evicts the PRC2 catalytic core from the substrate nucleosome. In cells, PRC2 transfers from chromatin to pre-mRNA upon gene activation, and chromatin-associated G-tract RNA removes PRC2, leading to H3K27me3 depletion from genes. Targeting G-tract RNA to the tumor suppressor gene CDKN2A in malignant rhabdoid tumor cells reactivates the gene and induces senescence. These data support a model in which pre-mRNA evicts PRC2 during gene activation and provides the means to selectively remove PRC2 from specific genes.
Project description:This SuperSeries is composed of the following subset Series: GSE33653: Direct Recruitment of Polycomb Repressive Complex 1 (PRC1) to Chromatin by Core Binding Transcription Factors (ChIP-Seq) GSE33659: Direct Recruitment of Polycomb Repressive Complex 1 (PRC1) to Chromatin by Core Binding Transcription Factors (microarray) Refer to individual Series
Project description:This SuperSeries is composed of the following subset Series: GSE33546: Polycomb repressive complex 2-dependent and M-bM-^@M-^Sindependent functions of Jarid2 in transcriptional regulation in Drosophila [ChIP-Seq] GSE36038: Polycomb repressive complex 2-dependent and M-bM-^@M-^Sindependent functions of Jarid2 in transcriptional regulation in Drosophila [Affymetrix] Refer to individual Series
Project description:Polycomb repressive complexes (PRCs) play key roles in developmental epigenetic regulation. Yet the mechanisms that target PRCs to specific loci in mammalian cells remain incompletely understood. In this study, we show that Bmi1, a core component of Polycomb Repressive Complex 1 (PRC1), binds directly to the Runx1/CBFbeta transcription factor complex. Genome-wide studies in megakaryocytic cells demonstrate considerable chromatin occupancy overlap between the PRC1 core component Ring1b and Runx1/CBFbeta and functional regulation of a significant fraction of commonly bound genes. Bmi1/Ring1b and Runx1/CBFbeta deficiency generate partial phenocopies of one another in vivo. We also show that Ring1b occupies key Runx1 binding sites in primary murine thymocytes and that this occurs via Polycomb Repressive Complex 2 (PRC2) independent mechanisms. Genetic depletion of Runx1 results in reduced Ring1b binding at these sites in vivo. These findings provide evidence for site-specific PRC1 chromatin recruitment by core binding transcription factors in mammalian cells. shRNA mediated knockdown of CBFb, Ring1b and control in biological triplicate
Project description:We show that Polycomb repressive complexes (PRCs) regulate lineage choice between neural and non-neural fates in the olfactory epithelium. Conditional loss of Polycomb repressive complex 2 perturbs lesion-induced neurogenesis and misexpression of lineage-specific transcription factors in multipotent olfactory globose basal cells.